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This post was last edited by slll611 on 2016-1-31 at 20:52. Dear friends, for the daily environmental protection question on January 30th, I selected a question related to energy conservation; however, I made an error in formulating it. Since the topic involved transformers and I’m not an expert in that area, I provided an explanation based on the answer I found. Later, a friend said they had seen the answer online to be the exact opposite, so I changed the answer again. Upon careful checking, it turns out that the original answer seems to be correct, which has caused confusion among everyone. I sincerely apologize to all of you for not verifying things carefully when creating the questions and for failing to fulfill my responsibilities; please feel free to criticize me. Experts in this field are also welcome to share their views on this topic. We will find a way to compensate everyone for the incorrectly assigned scores. Below are some information available online regarding transformer losses; experts are welcome to discuss them in order to clarify these matters. One theory is: “1. Active power loss The active power loss in electrical transformers includes iron loss and copper loss.” Among them, iron loss, also known as no-load loss, depends on the material of the core and remains essentially constant regardless of the load level. Copper loss is proportional to the square of the load current, and the copper loss at the rated load current is referred to as short-circuit loss. 2. Reactive power loss The reactive power loss in power transformers consists of excitation (no-load) current loss and leakage magnetic flux loss. The excitation (no-load) current loss Q0 depends on the core and is independent of the load. The leakage magnetic loss Q represents the leakage magnetic reactance loss of the primary and secondary windings, and its value is proportional to the square of the load current. ” Another way of putting it is: “The losses in a transformer include copper loss and iron loss.” Copper loss is the heating loss due to the resistance of the coil. Heat loss is related to factors such as the material of the coil wires, wire length, wire diameter, and ambient temperature. The longer the wire (the more turns it has), the greater the copper loss; higher ambient temperatures also lead to increased copper loss. Iron loss includes core eddy current loss and magnetic leakage loss. Iron loss is related to factors such as the magnetic permeability of the silicon steel sheets in the core, the thickness of these sheets, their surface insulation properties, and the degree of tightness with which the sheets are stacked. The lower the losses of a transformer, the higher its efficiency; a well-designed and high-quality transformer can achieve an efficiency of 90% or even 95% or more. To reduce heat generation and lower temperatures, large transformers are often immersed in insulating transformer oil, and this oil is used by radiators to dissipate heat into the air, thereby reducing the temperature rise of the transformer and maintaining high efficiency. ” Another way of putting it is: “The active and reactive losses of power transformers. The active losses of transformers are divided into constant active losses (iron loss) and variable active losses (copper loss).” The reactive power loss of a transformer is also divided into two categories: constant reactive power loss and variable reactive power loss. 1. Active power loss. It is approximately equal to the rated copper loss multiplied by the ratio of the apparent current (load current) to the square of the rated current. That is: variable active loss = rated copper loss × (load current/rated current) squared. 2. Variable reactive power loss. It is approximately equal to the product of the percentage of the rated short-circuit voltage and the ratio of the rated capacity to the square of the (load current) divided by the rated current. That is: variable reactive loss = percentage of rated short-circuit voltage × rated capacity × (load current/rated current) squared. Further question: what is the relationship between active and reactive power, as well as eddy current losses, and hysteresis losses? The answer is that a transformer consists of wires and an iron core. During operation, the wires generate heat, and eddy currents are produced as the iron core conducts magnetism, resulting in heat release. All heat released in the form of thermal energy is referred to as active loss. Hysteresis refers to the heat loss that occurs when residual magnetism is not fully converted into electricity in the secondary coil. In fact, electricity, magnetism, and light are all forms of electromagnetic waves. ” Calculation of transformer losses: Transformer losses consist of two parts: no-load loss and load loss. 1. No-load loss of the transformer: The no-load loss of a transformer, also known as iron loss, is a type of excitation loss that is independent of the load. 1.1 Composition of no-load loss: Typically, the no-load loss of a transformer consists of hysteresis loss and eddy current loss of the core material, as well as additional losses.